Main function: Mini,portable necklace design, and convenient to carry.Multi functions to purify indoor air.Release anion groups, air quality effectively.Easy to operate, one button for on/off.Rechargable lithium battery.Product Specification: Power Supply: USB Working principle: anions Applicable area: 10m Functions: air fresher Filter type: no Anion density: 1m Noise: 25dB Battery capacity: 250mAh Colour: Black Material: ABS Size: 70 * 26 * 15mm Package Contents: 1 * air purifier 1 * usb cable 1 * lanyard 1 * Manual Only the above package content, other products are not included.Note: Light and different displays may cause the color of the item in the a little different from the real thing.The measurement allowed error is +/- 1-3cm.